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United States Patent |
6,097,911
|
Watanabe
,   et al.
|
August 1, 2000
|
Process cartridge having shiftable cover with specific spacing between
cover and cartridge
Abstract
A process cartridge detachably mountable within an image forming system,
includes an image bearing member, a process device for processing the
image bearing member, a housing for supporting the image bearing member
and the process device, and a cover shiftable between a protecting
position where the image bearing member is protected and a retard position
where the cover is retarded from the protecting position. The cover is
spaced apart between 20-50 mm from the housing at least in the retard
position. An image forming system includes mounting equipment for mounting
such a process cartridge, an airflow generator for generating an airflow
passing through between the housing and the cover, a transfer mechanism
for transferring a developed image formed on the image bearing member onto
a recording medium, and a conveying mechanism for conveying the recording
medium.
Inventors:
|
Watanabe; Kazushi (Yokohama, JP);
Tsuda; Tadayuki (Kawasaki, JP);
Shirai; Hiroyuki (Tokyo, JP);
Komatsu; Teruo (Yokohama, JP);
Ikemori; Ikuo (Yokohama, JP)
|
Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
Appl. No.:
|
480388 |
Filed:
|
June 7, 1995 |
Foreign Application Priority Data
| Dec 20, 1991[JP] | 3-338597 |
| Mar 12, 1992[JP] | 4-53695 |
Current U.S. Class: |
399/114 |
Intern'l Class: |
G03G 021/18 |
Field of Search: |
555/200,210,211,245,260
399/92,111,114
|
References Cited
U.S. Patent Documents
3985436 | Oct., 1976 | Tanaka et al. | 355/200.
|
4462677 | Jul., 1984 | Onoda | 355/210.
|
4470689 | Sep., 1984 | Nomura et al. | 355/211.
|
4540268 | Sep., 1985 | Toyono et al. | 355/210.
|
4708455 | Nov., 1987 | Kubota et al. | 355/211.
|
4829334 | May., 1989 | Takamatsu et al. | 355/211.
|
4875077 | Oct., 1989 | Takamatsu et al. | 355/212.
|
4941015 | Jul., 1990 | Komai et al. | 355/200.
|
5083158 | Jan., 1992 | Kashima et al. | 355/200.
|
5113220 | May., 1992 | Kwak | 355/200.
|
Foreign Patent Documents |
3220538 | Dec., 1982 | DE.
| |
59-061865 | Apr., 1984 | JP.
| |
58446 | Apr., 1984 | JP | 355/211.
|
59-165072 | Sep., 1984 | JP.
| |
0114872 | Jun., 1985 | JP | 355/211.
|
0244472 | Sep., 1989 | JP | 355/211.
|
2011158 | Mar., 1990 | JP.
| |
2101933 | Jan., 1983 | GB.
| |
Primary Examiner: Beatty; Robert
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Parent Case Text
This application is a continuation of application Ser. No. 08/372,842 filed
Jan. 13, 1995, now U.S. Pat. No. 5,878,304 which is a continuation of
application Ser. No. 07/861/370 filed Mar. 31, 1992, now abandoned.
Claims
What is claimed is:
1. A process cartridge removably mountable onto a main body of an
electrophotographic image forming apparatus, said process cartridge
comprising:
(a) a cartridge frame;
(b) an electrophotographic photosensitive member;
(c) process means acting on said electrophotographic photosensitive member;
and
(d) cover movable between a closed position in which said cover covers a
revealed portion, revealed from said cartridge frame, of said
electrophotographic photosensitive member and an open position in which
said cover is retracted from said closed position to reveal said
electrophotographic photosensitive member from said cartridge frame,
wherein said cover includes a covering portion for covering said revealed
portion, revealed from said cartridge frame, of said electrophotographic
photosensitive member and a supporting portion for supporting said
covering portion so that said covering portion is movable between said
closed position and said open position, said supporting portion being
rotatable connected to said cartridge frame,
wherein said cover further comprises a projection member on said cover; and
wherein when said process cartridge is mounted on said main body of said
electrophotographic image forming apparatus, a member connected to said
cover is in contact with an abutment portion provided on said main body to
open said cover, wherein when said shutter is in said open position, the
distance between said covering position and said cartridge frame is from
20 mm to 50 mm.
2. A process cartridge removably mountable onto a main body of an
electrophotographic image forming apparatus, said process cartridge
comprising:
(a) a cartridge frame;
(b) an electrophotographic photosensitive member;
(c) a charging member for charging said electrophotographic photosensitive
member;
(d) a developing member for developing a latent image formed on said
electrophotographic photosensitive member; and
(e) a cover movable between a closed position in which said cover covers a
revealed portion, revealed from said cartridge frame, of said
electrophotographic photosensitive member and an open position in which
said cover is retracted from said closed position to reveal said
electrophotographic photosensitive member from said cartridge frame,
wherein said cover includes a covering portion for covering said revealed
portion, revealed from said cartridge frame, of said electrophotographic
photosensitive member and a supporting portion for supporting said
covering portion so that said covering portion is movable between said
closed position and said open position, said supporting portion being
rotatably connected to said cartridge frame,
wherein said cover further comprises a projection member on said cover; and
wherein when said process cartridge frame is mounted on said main body of
said electrophotographic image forming apparatus, a member connected to
said cover is in contact with an abutment portion provided on said main
body to open said cover, and
wherein when said cover is in said open position, a distance between said
covering portion and said cartridge frame is from 20 mm to 50 mm.
3. A process cartridge according to claim 2, wherein when said process
cartridge is mounted on said main body of said electrophotographic image
forming apparatus, said covering portion of said shutter is in contact
with said abutment portion of said main body so that said shutter remains
in said open position.
4. A process cartridge according to claim 2, wherein when said process
cartridge is mounted on said main body of said electrophotographic image
forming apparatus, said supporting portion of said shutter is in contact
with said abutment portion of said main body so that said shutter remains
in said open position.
5. A process cartridge according to claim 3, wherein when said shutter is
in said open position, a lower end of said covering portion is in contact
with said abutment portion of said main body.
6. A process cartridge according to claim 4, wherein when said shutter is
in said open position, a lower end surface of said supporting potion is in
contact with said abutment portion of said main body.
7. A process cartridge according to claim 2 further comprising:
a cleaning member for removing a developer remaining on said
electrophotographic photosensitive member.
8. An electrophotographic image forming apparatus, onto which a process
cartridge is removably mountable, for forming an image on a recording
medium, said electrophotographic image forming apparatus comprising:
(a) an abutment portion provided on a main body;
(b) mounting means for removably mounting said process cartridge on said
main body, said process cartridge including:
(i) a cartridge frame;
(ii) an electrophotographic photosensitive member;
(iii) a charging member for charging said electrophotographic
photosensitive member;
(iv) a developing member for developing a latent image formed on said
electrophotographic photosensitive member; and
(v) a cover movable between a closed position in which said cover covers a
revealed portion, revealed from said cartridge frame, of said
electrophotographic photosensitive member and an open position in which
said cover is retracted from said closed position to reveal said
electrophotographic photosensitive member from said cartridge frame,
wherein said cover includes a covering portion for covering said revealed
portion, revealed from said cartridge frame, of said electrophotographic
photosensitive member and a supporting portion for supporting said
covering portion so that said covering portion is movable between said
closed position and said open position, said supporting portion being
rotatably connected to said cartridge frame,
wherein said cover further comprises a projection member on said cover; and
wherein when said process cartridge is mounted on said main body of said
electrophotographic image forming apparatus, a member connected to said
cover is in contact with said abutment portion of said main body to open
said cover, and
wherein when said cover is in said open position, the distance between said
covering portion and said cartridge frame is from 20 mm to 50 mm; and
(c) a conveying member for conveying said recording medium.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process cartridge and an image forming
system within which such a process cartridge can be mounted. The image
forming system may be an electrophotographic copying machine, a laser beam
printer (LBP), a facsimile system, a word processor or the like.
2. Related Background Art
In the past, an image forming system having a removable process cartridge
including a desired process means necessary for forming an image, which
thereby permits easy replacement of the cartridge due to the expiration of
the service life of the cartridge or the like has been proposed (refer to
U.S. Pat. No. 3,985,436). Further, a plurality of process cartridges
having developer of different colors therein can be used to form a color
image, and thus, have a high frequency of exchange, and in some cases, the
process cartridge alone is disposed outside the image forming system.
Under those circumstances, it is necessary to prevent a photosensitive
member from being smudged or damaged and to prevent the photosensitive
member from being exposed to light (which leads to the deterioration of
the photosensitive member). To this end, the process cartridge is provided
with a cover member for protecting the photosensitive member and shielding
the interior of the cartridge from ambient light.
The inventors invented the particularly effective techniques in this
technical field and disclosed them in U.S. Pat. Nos. 4,470,689 and
4,462,677 and in the Japanese Patent Publication No. 2-11158 (published on
Mar. 13, 1990).
The present invention relates to the improvement in the above invented
techniques.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process cartridge and an
image forming system which can further enhance the image quality.
Another object of the present invention is to provide a process cartridge
and an image forming system which can be protected from a bad influence of
heat.
A further object of the present invention is to provide a process cartridge
and an image forming system which can discharge heat effectively.
A still further object of the present invention is to provide a process
cartridge and an image forming system wherein a protection member for
protecting an image bearing member from light and (or) smudge forms a part
of a fluid passage.
A further object of the present invention is to provide a process cartridge
and an image forming system which can prevent the deterioration of
features of an image bearing member due to heat.
A still further object of the present invention is to provide a process
cartridge and an image forming system wherein, when the process cartridge
is mounted within the image forming system, a protection member for
covering an opening of the process cartridge in its dismounted condition
is retarded from the opening completely to be positioned and spaced apart
from a frame of the process cartridge.
A further object of the present invention is to provide a process cartridge
which comprises an image bearing member, an action member acting on the
image bearing member, a frame for supporting the image bearing member and
the action member, and a protection member shiftable between a covering
position where it covers a surface of the image bearing member and a
retard position where it is retarded up to a lateral end of the frame, and
an image forming system within which such process cartridge can be
mounted.
Another object of the present invention is to provide an image forming
system which can prevent the inadvertent closing movement of a protection
member by providing a positioning member for positioning the protection
member at its open position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 to 4 are elevational sectional views of an electrophotographic
copying machine to which a preferred embodiment of the present invention
is applied;
FIG. 5 is an elevational view showing a relation between a cover of a
process cartridge and the copying machine;
FIGS. 6A and 6B are perspective views showing the relation between the
cover of the process cartridge and the copying machine;
FIG. 7 is an elevational view showing the arrangement of the cover of the
process cartridge;
FIG. 8 is an elevational sectional view of an electrophotographic copying
machine to which another embodiment of the present invention is applied;
FIG. 9 is an elevational sectional view of an electrophotographic copying
machine to which a further embodiment of the present invention is applied;
FIG. 10 is a perspective view of a process cartridge to which a further
embodiment of the present invention is applied;
FIG. 11 is a cross-sectional view of the process cartridge of FIG. 10;
FIG. 12 is an elevational sectional view of a laser beam printer to which
an embodiment of the present inventions is applied;
FIG. 13 is a cross-sectional view of a process cartridge to which a still
further embodiment of the present invention is applied;
FIG. 14 is a perspective view of a process cartridge to which a further
embodiment of an present invention is applied;
FIG. 15 is a cross-sectional view of a process cartridge to which a still
further embodiment of the present invention is applied;
FIG. 16 is a perspective view of a process cartridge to which a further
embodiment of present invention is applied;
FIG. 17 is an elevational sectional view of a main portion of a laser beam
printer to which another embodiment of the present invention is applied;
FIG. 18 is an elevational sectional view of a main portion of a laser beam
printer to which a further embodiment of the present invention is applied;
FIG. 19 is an elevational sectional view of a main portion of a laser beam
printer to which a still further embodiment of the present invention is
applied;
FIG. 20 is an elevational sectional view of a laser beam printer to which a
further embodiment of the present invention is applied;
FIG. 21A is a plan view of a regulating member, FIG. 21B is an end view of
the regulating member of FIG. 21A;
FIG. 22A is a perspective view showing a relation between a process
cartridge and a regulating member of a machine to which the other
embodiment of the present invention is applied, in a condition that a drum
protection member is closed, FIG. 22B is an end view showing a relation
between the process cartridge of FIG. 22A and the regulating member of the
machine;
FIG. 23A is a perspective view showing a condition that the drum protection
member is opened, FIG. 23B is an end view showing the condition that the
drum protection member is opened;
FIG. 24 is an elevational sectional view of a laser beam printer to which a
further embodiment of the present invention; and
FIG. 25 is an elevational sectional view of a laser beam printer to which
the other embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be explained in connection with embodiments
thereof with reference to the accompanying drawings.
Incidentally, in the following embodiment, an image forming system is
illustrated as an electrophotographic copying machine, as an example.
FIG. 1 is an elevational sectional view of the electrophotographic copying
machine 1 within which a process cartridge 2 is mounted, in an operative
condition. FIG. 2 is an elevational sectional view of the copying machine
1 showing a condition that it is opened. As shown in FIG. 2, the copying
machine according to this embodiment includes an upper frame 9 pivotally
mounted, via a pins 9c, on a body frame of the machine 1. When the process
cartridge 2 is desired to be mounted within the copying machine 1, after
an original support glass plate 20 and an original cover 21 (which will be
described later) are manually retarded leftwardly, the upper frame 9 is
opened, and the process cartridge 2 is mounted on the upper frame 9 by
locking the former to guides 9a, 9b of the latter. Thereafter, the upper
frame 9 is closed, and the original support glass plate 20 and the
original cover 21 are returned to a predetermined original position.
Incidentally, a leaf spring 34 is fixed to the body frame of the machine
1. Thus, when the upper frame 9 is closed, it is locked by the leaf spring
34. Further, the upper frame 9 carries a lamp L for illuminating a surface
of an original and a lens 4 for directing a light image reflected from the
surface of the original to an electro-photographic photosensitive member
5, which elements L, 4 act as optical members for exposing the original.
Now, the electrophotographic copying machine to which this embodiment is
applied will be explained.
The reference numeral 20 denotes the above-mentioned original support glass
plate on which an original can be rested and which can be reciprocally
moved in directions shown by the arrow A. The reference numeral 21 denotes
the above-mentioned original cover. The original rested on the original
support glass plate 20 is illuminated by the lamp L, and a light image
reflected from the surface of the original is directed to the
electrophotographic photosensitive member 5 via the lens 4. When the light
image is illuminated on the photosensitive member 5 previously charged by
a charger 22, a latent image is formed on the photosensitive member. Then,
the latent image is developed by a developing device 23 having a
developing sleeve 23a for feeding toner to the photosensitive member 5 to
develop the latent image. The developed image is then transferred, by a
transfer charger 18, onto a recording medium P such as a recording sheet
fed from a manual sheet supply plate 24 by a sheet supply roller 13 and
sent to the photosensitive member 5 in registration with the developed
image by a pair of register rollers 29 and a guide 33. Incidentally, an
urging pad 13a cooperates with the sheet supply roller 13 to separate the
recording media P one by one. Then, the recording medium P is guided by
guides 17, 25 to reach a fixing device 14 (including a heat roller 14a and
a pressure roller 14b), where the developed image is fixed to the
recording medium. After the fixing operation, the recording medium is
ejected onto a tray 27 by ejector rollers 26. On the other hand, after the
developed image is transferred, a surface of the photosensitive member 5
is cleaned by a cleaning device 28 having a cleaning blade 28a for
removing the residual toner from the photosensitive member 5.
Incidentally, the reference numeral 15 denotes a fan (for example, cross
flow fan) for generating air flows a-g; 30 denotes a convey roller; and 35
denotes an air outlet.
Next, an embodiment of a process cartridge to which the present invention
is applied will be explained with reference to FIGS. 1 to 6. Incidentally,
FIG. 3 is an elevational sectional view showing a condition that the upper
frame 9 is opened with respect to the body frame of the copying machine,
FIG. 4 is an elevational sectional view showing a condition that the upper
frame 9 is closed with respect to the body frame of the copying machine,
FIG. 5 is a side view of a cover 8 of the process cartridge 2, and FIGS.
6A and 6B are perspective views of the cover. The cover 8 and a frame 31
of the process cartridge 2 is formed from HIPS resin (high impact
polystyrol resin) of high impact type among polystyrene resin materials.
The material of the process cartridge is not limited to the above resin,
but may be fast resin such as polyphenyleneoxide (PPO).
The process cartridge according to this embodiment has a frame 31
integrally supporting therein a photosensitive drum 5, a developing device
23, a cleaning device 28 and a charger 22 (these elements 23, 28, 22
serving as action means for acting on the photosensitive drum 5). The
frame 31 of the cartridge can be removably mounted on the upper frame 9 of
the copying machine 1. The frame 31 is designed so that a transfer area
31a and an image exposure area 31b of the photosensitive drum 5 are
exposed, and covers 8, 7 for protecting these areas are provided for
opening/closing movements. Incidentally, an opening/closing mechanism 6
for the cover 7 for the exposure area 31b may be any one of conventional
mechanisms, and, thus, the explanation thereof will be omitted.
Next, an opening/closing mechanism for the cover 8 for protecting the
transfer area 31a of the photosensitive drum 5 will be explained.
The cover 8 has a cover portion 8p, and arm portions 8b integrally formed
with the cover portion 8p and extending therefrom at an angle of .theta.
of 120-130 degrees (FIG. 6). The cover portion 8p is so curved and shaped
that, when the cover is closed, the cover portion is conformed to a
peripheral surface of the photosensitive drum 5. Further, the arms 8b are
pivotally mounted on pins 8d, 8k formed on side walls 31c of the frame 31
of the cartridge 2, and a torsion coil spring 12 is arranged on the pin 8d
so that it biases the cover portion 8p toward its closed position. One end
12a of the torsion coil spring 12 is locked to the frame 31 of the
cartridge, and the other end 12b of the spring is engaged by a projection
8c formed on the arm 8b. Further, a cam 8a is fixedly mounted on one end
of the pin 8d so that the cam is rotated together with the arm 8b.
Now, the opening/closing movement of the cover 8 will be explained.
When the process cartridge 2 is in a condition that it is detached from the
copying machine 1, the cover 8 is so positioned, by the torsion coil
spring 12, that the cover portion 8p covers the surface of the
photosensitive drum 5.
However, when the cartridge 2 is mounted on the guides 9a, 9b of the upper
frame 9 of the copying machine 1 (FIGS. 2 and 3) and the upper frame 9 is
closed, during the closing movement of the upper frame, a lower surface of
the cam 8a is abutted against a protrusion 10 fixedly formed on the
copying machine 1, thus being rotated in a clockwise direction. As a
result, the arms 8b are also rotated in the clockwise direction, thereby
opening the cover to expose the transfer area 31a of the photosensitive
drum 5. In the condition that the cover portion 8p is completely opened,
the cover portion 8p is retarded from the transfer area 31a and is shifted
up to a position corresponding to an end portion 31a' of the frame 31 of
the cartridge 2 to be spaced apart from the frame 31 (FIGS. 1, 4, 5 and
6). In this point, a free end 8i of the cover portion 8p is abutted
against positioned protrusions 16 fixedly formed on the copying machine 1.
Thus, the cover 8 is prevented from inadvertently moving to block a
feeding path for the recording medium.
FIG. 7 schematically shows the dimension of the cover 8 of the process
cartridge 2.
In the above-mentioned embodiment, a distance L.sub.1 between the pivot
pins 8d, 8k for the arms 8b and an edge of the cover portion 8p nearest to
the pivot pins is longer than a distance L.sub.2 between the pivot pins
8d, 8k and the end surface of the cartridge (L.sub.1 >L.sub.2). Thus, in
the condition that the cover portion 8p is opened, it is possible to space
the cover portion 8p apart from the frame 31 of the cartridge.
Furthermore, the pivot pins 8d, 8k for the arms 8b are offset toward the
end surface of the cartridge from a central point of a half (l/2) of a
distance l between a center 5a of the drum 5 and the end surface of the
cartridge ((l-L.sub.2)>1/2). Thus, it is possible to make the cartridge
thinner (more compact), and to space the cover portion 8p apart from the
frame 31 of the cartridge when the cover portion 8p is opened.
Next, the operation of the cover 8 will be explained.
As mentioned above, the process cartridge 2 has the cover 8 for protecting
the photosensitive member 5. When the upper frame 9 is opened with respect
to the body frame of the copying machine 1, as shown in FIG. 3, the cover
8 pivotally mounted on the frame 31 of the process cartridge 2 via the
pins 8d, 8k is biased toward the anti-clockwise direction by means of the
torsion coil spring 12 having one end 12a fixed to a portion of the
process cartridge 2 and the other end 12b engaged by the projection 8c of
the arm 8b of the cover 8 so that the cover 8 covers the photosensitive
member 5. When the upper frame 9 is closed with respect to the body frame
of the copying machine 1, as shown in FIGS. 4 to 6, the cam 8a secured to
the pin 8d for the arm 8b of the cover 8 is rotated in the clockwise
direction by the protrusion 10 secured to the copying machine 1.
Consequently, the cover 8 is rotated toward its open position. Thus, the
process cartridge 2 is mounted within the copying machine 2 with exposing
the photosensitive member 5, thereby bringing the copying machine to the
operative condition. In this point, the cover 8 has been completely
retarded from the lower portion of the process cartridge 2 and positioned
near one end surface of the cartridge between the process cartridge 2 and
the fixing device 14 and spaced apart from the process cartridge 2. The
cover 8 faces a housing of the developing device 28. Further, the free end
8i of the cover portion 8p is abutted against and properly positioned by
the protrusions 16 uprightly protruded from a bottom of the body frame of
the copying machine 1 on both outsides of (and perpendicular to) the sheet
feeding path (FIG. 6A). Incidentally, in the embodiment shown in FIG. 6A,
while an example that the abutment protrusions 16 support the free end 8i
of the cover portion 8p was explained, the present invention is not
limited to this example, but, the arms 8b may be supported by the
protrusions 16, as shown in FIG. 6B.
Next, a further embodiment of the present invention will be explained.
In the above-mentioned embodiments, the process cartridge 2 was mounted
within the image forming system by mounting the opened upper frame 9 of
the image forming system and then by closing the upper frame 9 with
respect to the system. However, it should be understood that these
embodiments can be carried out in an arrangement (as shown in FIGS. 8 and
9) wherein an optical frame 9d for opening and closing the upper opening
of the copying machine l merely carries the optical system (lamp L and
lens 4) (and is not provided with the guides 9a, 9b) and the process
cartridge 2 is mounted on a lower frame 1a of the copying machine 1 after
the optical frame 9d is opened.
Now, in the above-mentioned embodiments, when the process cartridge 2 is
mounted within the copying machine, the cover portion 8p can be retarded
from the opening of the process cartridge 2 and be positioned between the
process cartridge 2 and the fixing device 14 with spacing apart from the
process cartridge (Incidentally, the space or distance between the frame
of the process cartridge and the cover member may be about 20 mm-50 mm in
these embodiments). Further, in the condition that the cover portion 8p is
opened, a part of the cover portion 8p can be positioned in the copying
machine 1. Thus, according to the above-mentioned embodiments, the air
flows (a-g) generated by the heat discharging fan 15 are also generated
between the cover portion 8p and the process cartridge 2, thereby
remarkably enhancing the cooling ability for the process cartridge 2 and
the cover portion 8p, with the result that it is possible to prevent the
thermal deformation of the various elements and the melting of the toner
in the process cartridge. Further, since the cover portion 8p is held in
the open position after the cartridge is mounted within the copying
machine, the sheet feeding path is not restricted or blocked by the cover,
with the result that it is possible to prevent the poor feeding of the
recording medium P due to the contacting between the recording medium P
and the cover portion 8p, and the distortion of the toner image on the
recording medium. Furthermore, it is possible to make the image forming
system small-sized and to reduce capacity of the heat discharging fan.
Now, air flow paths will be fully explained. In the illustrated
embodiments, the fan 15 is positioned within the copying machine 1 at an
upper portion thereof opposite to the position where the manual sheet
supply plate 24 is disposed. The fan 15 starts to be driven, for example,
upon depressing a copy button (not shown) to generate the air flows. Main
air flows are designated by the arrows a-g. When the fan 15 is rotated,
the ambient air is introduced into the copying machine 1 mainly through a
manual sheet supply opening 24a for the manual sheet supply plate 24
(arrow a). The air flow a passes through the sheet supply roller 13 and is
directed toward the mounted cartridge 2 along the guide 32 (arrow b). A
part of the air flow b impinges against the frame 31 of the cartridge 2
(particularly, the housing of the developing device 23), thereby cooling
it. Further, a part of the air flow b enters into a space between the
photosensitive member 5 and the transfer charger 18 to reach the cleaning
device 28 (arrow c), thus cooling the photosensitive member 5 and the
cleaning device 28.
Meanwhile, a part of the air flow enters into the cartridge 2 along the
periphery of the photosensitive member 5, thus cooling the cleaning blade
28a and the like in the cartridge. A part of the air flow passed through
the transfer area 31a ascends along the frame 31 to pass between the end
surface 31a' of the frame 31 and the cover 8, thus reaching the fan (arrow
d). In this way, according to the illustrated embodiments, particularly,
since the air flow can pass between the end surface 31a' of the frame 31
and the cover 8, the air flow does not stagnate in the proximity of the
cartridge 2, thus remarkably enhancing the cooling ability for the
above-mentioned elements. Further, a part of the air flow passed through
the transfer area 31a goes straight to impinge against the fixing device
14 and is directed to the fan 15 together with the air flow (arrow f) in
the vicinity of the fixing device 14 (arrows e and f). The air flows
sucked into the fan 15 are discharged out of the copying machine 1 through
the air outlet 35 (arrow g).
In this way, according to the illustrated embodiments, it is possible to
suppress the increase in temperature in the interior of the copying
machine 1. Particularly, according to the illustrated embodiments, since
the air flow can pass between the frame 31 and the cover 8, it is possible
to suppress the increase in temperatures in the interior of the cartridge
2 and therearound.
A still further embodiment of the present invention will be explained.
In an embodiment described below, a laser beam printer 100 is used as the
image forming system.
First of all, a process cartridge 103 to which the present invention is
applied will be explained with reference to FIGS. 10 and 11. Incidentally,
FIG. 11 is a cross-sectional view of a process cartridge to which the
present invention is applied, and FIG. 10 is a perspective view of such
cartridge; these Figures show a condition that the cover is opened.
Incidentally, in FIG. 11, air flows are also shown by the arrows. However,
it should be noted that these air flows are generated after the cartridge
has been mounted within the laser beam printer. According to this
embodiment, a drum shutter 138 provided on a process cartridge 103 has a
ventilating guide portion so that cool air can be directed to a
photosensitive drum 131 and a cleaner member 137. In this way, it is
possible to suppress the increase in temperature of the cartridge 103
(particularly, the photosensitive drum 131 and the cleaner member 137
therein).
Now, the process cartridge 103 according to this embodiment will be
explained with reference to FIGS. 10 and 11.
In FIGS. 10 and 11, the reference numeral 131 denotes the above-mentioned
photosensitive drum rotatable in an counter-clockwise direction. The
reference numeral 132 denotes a charger roller for uniformly charging a
photosensitive member 131a on the surface of the drum. The charger roller
132 is urged against the photosensitive drum 131 by a spring 132a. The
reference numeral 137 denotes the above-mentioned cleaner member having an
elastic cleaning blade 136 urged against the photosensitive member 131a
and adapted to remove the residual toner remaining on the photosensitive
member 131a. The reference numeral 134 denotes a developing device having
a developing sleeve 134b for conveying toner contained in a toner
containing portion 134a to a peripheral surface of the photosensitive
member, and a doctor blade 134c for regulating a thickness of a toner
layer formed on a peripheral surface of the developing sleeve 134b. The
reference numeral 138 denotes the above-mentioned drum shutter mounted on
a shaft 138-1 arranged above the photosensitive drum 131 for pivotal
movement in directions B1 and B2. When the drum shutter is rotated in the
direction B1, the photosensitive member 131a is exposed, thus permitting
the transfer of the image. On the other hand, when the drum shutter is
rotated in the direction B2, the photosensitive member is covered by the
drum shutter, thus protecting the photosensitive member 131a.
The cartridge 103 according to this embodiment has a frame 103a supporting
the above-mentioned photosensitive drum 131, charger roller 132,
developing device 134, developer containing portion 134a, cleaner member
137 and drum shutter 138 therein. The frame 103a of the cartridge can be
mounted within an image forming system 100. Incidentally, in this
embodiment, the drum shutter 138 is formed from polycarbonate and the
frame 103a is formed from high impact styrol to enhance the anti-impact
feature, fastness and heat-resistance of them.
Now, the movement of the drum shutter 138 will be explained with reference
to FIGS. 10 and 11.
The drum shutter 138 is pivotally mounted on the frame 103a of the
cartridge at its base end via pins 138-1, 138-2 so that it can be rocked
in directions (shown by the arrows B1, B2) in response to opening/closing
movement of a front unit 112 (FIG. 12) provided on the printer 100. More
particularly, the printer 100 (FIG. 12) is provided with a lever 113
engaged by a pin 138-3 of the drum shutter 138 and shifted in response to
the opening/closing movement of the front unit 112. When the front unit
112 is opened, the lever 113 is lowered, with the result that the drum
shutter is closed by a biasing force of a spring and the like (not shown).
When the photosensitive drum 131 is exposed (i.e., when the cartridge 103
is in a condition that it is detached from the printer 100 or when the
front unit 112 is opened), since the drum shutter 138 is automatically
closed to cover the photosensitive drum 131, it is possible to prevent the
photosensitive drum 131 from being exposed by the ambient light or being
touched by the operator's hand inadvertently. Further, when the operator
closes the front unit 112, the pin 138-3 is lifted by the lever 113 to
open the drum shutter 138.
In the illustrated embodiment, as shown in FIG. 10, when the drum shutter
138 is opened, a central portion of an inner surface (opposing to the
photosensitive drum 131) of the drum shutter 138 is protruded outwardly to
create a space or clearance S between a housing 139 of the process
cartridge 103 and the shutter. That is to say, a longitudinal protruded
member 138-4 is formed on the inner surface of the drum shutter 138, and a
clearance 138-5 (about 2-5 mm in this embodiment) is created between the
protruded member 138-4 and the housing 139. In this case, when the drum
shutter 138 is closed, since the protruded member is positioned in the
vicinity of or abutted against the housing 139 of the cartridge 103, thus
further preventing the photosensitive drum 131 from being exposed to the
ambient light. Incidentally, the reference numeral 138-7 denotes a rotary
support shaft for the photosensitive drum; and 138-8 denotes a grip.
Next, the laser beam printer 100 within which the process cartridge 103 can
be mounted and which can form an image will be explained with reference to
FIGS. 11 and 12.
The laser beam printer to which the present invention is applied comprises
a fixing portion disposed directly about a transfer portion and is so
designed that it utilizes a process cartridge incorporating various
electrophotographic processes therein, thereby making the printer
small-sized and reducing the increase in the temperature of the process
cartridge.
In FIGS. 11 and 12, a laser beam L emitted from a laser unit (not shown) of
a scanner unit 102 is deflected by a polygonal mirror 121 and then is
focused on the photosensitive drum 131 (rotated in a direction shown by
the arrow) through focusing lenses 122, 123.
A charger roller 132 for uniformly charging the photosensitive member 131a
is disposed at an upstream side of an exposure position for the laser beam
L. An electrostatic latent image formed on the photosensitive drum 131 by
the laser beam L is visualized by the developing device 134 having the
developing sleeve 134b to which the bias voltage is applied.
On the other hand, a transfer sheet P in a sheet supply cassette 104 is
supplied by a sheet supply roller 141 and is fed between the
photosensitive drum 131 and a transfer roller 135. The visualized image on
the photosensitive drum 131 is transferred onto the transfer sheet P by
the bias voltage of the transfer roller 135. The transfer sheet P to which
the image was transferred passes through between a fixing roller 152
(having a heater 141) and a pressure roller 153 of a fixing device 105,
where the visualized image is permanently fixed to the transfer sheet.
Thereafter, the transfer sheet P is ejected onto an ejection tray 111.
Incidentally, the residual toner remaining on the photosensitive drum 131
is removed by the cleaner 137 having the cleaning blade 136.
Incidentally, the above-mentioned photosensitive drum 131, charger roller
132, developing device 134 and cleaner 137 are contained within the
process cartridge 103. Further, the reference numeral 125 denotes a font
mounting portion on which fonts 125a are mounted.
In this way, by feeding the transfer sheet upwardly, it is possible to
arrange the process elements closely, thus making the printer compact or
small-sized.
Next, air flows generated in forming the image by the laser beam printer
100 within which the process cartridge 103 is mounted will be explained
with reference to FIGS. 11 and 12.
In this embodiment, a fan 110 is disposed below an outlet 106 for the sheet
P to be ejected and at an end of the printer 100. When the fan (for
example, axial flow fan in this embodiment) 110 is rotated, the ambient
cool air is introduced into the printer through clearances at the front
unit 112, sheet supply roller 141 and the like (arrows W.sub.1, W.sub.2).
The air flows W.sub.1, W.sub.2 pass through the vicinity of the transfer
roller 135 (arrow W.sub.3) to reach the cartridge 103. A part of this air
flow passes by the lateral side of the fixing device 105 (arrow W.sub.4)
and then is discharged from the printer through an opening 114-1 (arrow
W.sub.6). Further, a part of the above-mentioned air flow passes through
the vicinity of the photosensitive drum 131 and through the space S
between the housing 139 of the cartridge 103 (particularly, housing
portion positioned near a free end portion 137-1 of the cleaner 137) and
the drum shutter 138 (arrow W.sub.5) and then is discharged from the
printer through an opening 115-1 (arrow W.sub.7).
In this way, according to this embodiment, the air discharging fan 110 is
disposed at ends of air flow passages 114, 115, and the air in the
cartridge 103 is sucked into the printer mainly through the openings
114-1, 115-1 formed in a partition wall 116 for the air flow passages 114,
115 and then is discharged from the printer 100.
Next, further embodiments of the present invention will be explained with
reference to FIGS. 13 to 15, among which FIG. 13 is a cross-sectional view
of a process cartridge 103 to which the further embodiment of the present
invention is applied.
In this embodiment, one or several cam-shaped ribs 138-5 eccentric from the
pivot pins 138-1, 138-2 for the drum shutter 138 are arranged along the
longitudinal direction of the shutter. According to this embodiment, when
the drum shutter 138 is rotated, the rib 138-5 is abutted against the
housing 138 of the cartridge, with the result that the drum shutter 138 is
flexed to create the clearance S between shutter 138 and the housing 139
of the cartridge.
FIG. 14 is a perspective view of a process cartridge 103 according to a
still further embodiment of the present invention, in which a central
portion of the drum shutter 138 has a longitudinal cut-out or notched
portion 138-6. According to this embodiment, the clearance S is created
between the drum shutter 138 and the cartridge housing 139 by the notched
portion 138-6.
FIG. 15 shows a further embodiment of the present invention. In this
embodiment, unlike to the above-mentioned embodiments wherein the drum
shutter 138 is pivotable, the drum shutter 138 can be opened and closed by
being slid by a slide mechanism (not shown) such as a link mechanism in
the vicinity of the surface of the photosensitive drum 131. Also in this
embodiment, a protruded member 138-7 may be formed on the front central
portion of the drum shutter 138 or a notched portion 138-8 may be formed
in the rear central portion of the shutter to create the clearance, so
that the advantage same as those of the previous embodiments can be
obtained.
Further embodiments will be explained with reference to FIGS. 16 to 19.
The embodiments which will be described hereinbelow show (1) an example
that a shield member for preventing the entrance of air flow into
predetermined areas is formed on the above-mentioned drum shutter, and (2)
an example that a shield member for cooperating with the drum shutter to
prevent the entrance of air flow into predetermined areas is formed on an
image forming system. Incidentally, these embodiments will be described
hereinbelow as examples that these are applied to the laser beam printer
shown in FIG. 12.
Now, FIG. 16 is a perspective view of a process cartridge 203 relating to
the above example (1), and FIG. 17 is a partial elevational sectional view
showing the air flows in forming the image by using the laser beam printer
100 within which the process cartridge 203 was mounted. Incidentally,
FIGS. 18 and 19 are partial elevational sectional views showing the above
example (2).
In the embodiment shown in FIGS. 16 and 17, a longitudinal rib 138-9 (a
protruding amount (from the surface of the drum shutter) of which is about
5 mm) is formed on a back surface the drum shutter 138 (a surface opposite
to the photosensitive drum 131 when the shutter is closed). When the
cartridge 203 is mounted within the printer 100 and the drum shutter 138
is opened, the rib 138-9 is positioned to be abutted against or
substantially abutted against the air discharging opening 114-1 of the
printer 100. That is to say, the rib 138-9 is positioned so that a free
end of the rib is situated in the proximity of the lower partition wall
116 for the opening 144-1. Thus, an air flow W.sub.4 including hot air and
passing through the vicinity of a fixing device 105 or the interior of the
fixing device is blocked by the rib 138-9 (This condition is shown by the
arrow W.sub.8). Accordingly, the high temperature air flow is ejected out
of the printer through the opening 114-1, without flowing toward an upper
surface 203-1 of the housing of the cartridge 203 (air flow W.sub.6).
According to this embodiment, it is possible to obtain air passages same as
those as mentioned above. Thus, the constructural elements in the
cartridge 203 (for example, photosensitive drum 131, toner and the like)
can be prevented from being exposed to the high temperature air. Further,
since the cool air always flows through the vicinity and interior of the
cartridge 203, it is possible to further suppress the increase in
temperature of these constructural elements.
Next, in an embodiment shown in FIG. 18, a partition member 117 for
abutting against the drum shutter 138 is secured to the lower partition
wall 116 for the air discharging opening 114-1 of the printer. The
partition member 117 has a width substantially the same as that of the
drum shutter 138 and is slightly bent toward the drum shutter 138 so that
it is apt to be abutted against the drum shutter 138. According to this
embodiment, when the drum shutter 138 is rotated to reach the open
position, the drum shutter is abutted against the partition member 117,
thus surely directing the air flow W.sub.4 to the opening 114-1.
Incidentally, in this embodiment, the partition member 117 is made from
plastic material to give it the elasticity.
In this case, when the partition member 117 is made from elastically
deformable materials (for example, resin, rubber, foam materials or the
like) or is formed to have the elasticity or flexibility, the excellent
advantage can be obtained. In this way, it is possible to perform the
pivotal movement of the drum shutter 138 smoothly, thus ensuring the
predetermined air passages.
On the other hand, in an embodiment shown in FIG. 19, the drum shutter 138
is not rotated, but is slid in the vicinity of the surface of the
photosenitive drum 131. Also in this case, the rib 138-9 may be formed on
the back surface of the drum shutter 138 so that the rib can be abutted
against the partition wall 116 for the air discharging opening 114-1 or be
positioned in the proximity of the partition wall, thus obtaining the same
advantage as the above one.
In this way, according to the embodiments shown in FIGS. 17 to 19, since
the air flows including the hot air are prevented from directing to the
vicinity of the cartridge, it is possible to further suppress the increase
in temperature of the cartridge. Further, according to the embodiments
shown in FIGS. 16 and 17, since the protruded portion 138-4 is positioned
in the vicinity of or abutted against the cartridge housing 139 when the
drum shutter 138 is closed, the photosensitive drum 131 is prevented from
being exposed to the ambient light or is hard to be damaged by foreign
matters or the operator's finger.
Next, other embodiments of the present invention will be explained with
reference to FIGS. 20 to 25. Incidentally, in embodiments which will be
described hereinbelow, an air intake opening is formed on a side wall of
the laser beam printer 100 at its upper part, so that the ambient cool air
can be introduced into the printer mainly from upper and lower portions
thereof, thus further enhancing the cooling efficiency for the process
cartridge.
Incidentally, constructural elements same as those of the previous
embodiments are designated by the same reference numerals, and the
detailed explanation thereof will be omitted. FIG. 20 is an elevational
sectional view of the laser beam printer, FIG. 21A is a longitudinal
partial plan view of a regulating member for maintaining a protection
member of the cartridge in an open condition, FIG. 21B is an end view of
the regulating member, FIGS. 22A and 23A are perspective views of an
opening/closing mechanism for the protection member of the cartridge, and
FIGS. 22B and 23B are end views of such mechanism. Incidentally, FIGS. 24
and 25 are elevational sectional views of laser beam printers to which the
other embodiments of the present invention are applied.
When a process cartridge 302 is inserted into a laser beam printer 300
(from a direction shown by the arrow V), a protection member 309 for
protecting an image bearing member 5 of the process cartridge 302 from
light, external force, smudge and the like is shifted from a protecting
position (closed position) to a retard position (open position).
Incidentally, an opening/closing mechanism for the protection member 309
will be explained later. In this case, the process cartridge 302 can be
correctly mounted in a predetermined position, because an upper surface
302b of the cartridge is abutted against a position regulating member 308
disposed at an upper part of a cartridge mounting position, thus
regulating a position of the cartridge in an upward direction. Further, in
this case, a rear end 309d of the protection member 309 is abutted against
a flow rectifying plate 308b pivotally provided on the position regulating
member 308 along the transversal direction of the printer to lift this
flow rectifying plate 308b, thus maintaining this plate in a slightly
downwardly inclined position.
Incidentally, the flow rectifying plate 308b is made from flexible material
such as resin and the like and has an attachment portion 308b2 and a flow
rectifying portion 308b1 pivotable with respect to the attachment portion
308b2. Further, the flow rectifying portion 308b1 is obliquely formed with
respect to the attachment portion 308b2 and is apt to be pivoted due to
the presence of notches 308b3.
In this condition, when a copy button (not shown) is turned ON, a fan 15 is
rotated to suck the air through an air introduction opening 300a formed in
a side wall of the printer 300 at its upper part and from a sheet supply
portion, thus generating air flows (W.sub.1 -W.sub.9) flowing around the
process cartridge 302 and directing toward the fan 15. Now, the air flow
W.sub.3 flowing along the upper surface of the process cartridge 302
impinges against and blocked by a wall 305b of the position regulating
member 308, with the result that this air flow passes through a clearance
between a housing 302a of the process cartridge 302 and an inner surface
of the protection member 309 (air flow W.sub.4). This air flow w.sub.4
impinges against a sheet conveying surface (guide 25) and changes its flow
direction between the sheet conveying surface 25 and the protection member
309 to be directed upwardly (air flow W.sub.6), and then flows toward the
fan 15 as the air flows W.sub.7, W.sub.8 toward the fan 15 from which they
are ejected out of the printer (air flow W.sub.9).
Next, the movements of the protection member 309 and the position
regulating member 308 in mounting the process cartridge 302 within the
printer 300 will be explained with reference to FIGS. 22A, 22B and 23A,
23B.
FIGS. 22A and 22B show a condition that the process cartridge 302 starts to
be mounted on a predetermined position within the printer 300. From this
condition, when the housing 302a of the process cartridge 302 is inserted
toward the direction V, first of all, a cover moving link 309b for opening
a cover 309a of the protection member 309 is abutted against a protrusion
310 of the printer. When the housing 302a of the process cartridge is
further inserted, the cover moving link 309b is rotated around a pivot pin
309b1, with the result that the cover 309a of the protection member
attached to a pivot pin 309b2 positioned on the other end of the link 309b
(opposite to an end which is abutted against the protrusion 310 with
respect to the pivot pin 309b1) is gradually opened while being guided by
a movable link 309c. When the housing 302a of the process cartridge is
completely inserted, the cover 309a of the protection member is abutted
against the flow rectifying plate 308b of the position regulating member
308 as mentioned above, thus rotating the flow rectifying portion 308b1
around a pivot portion (reduced thickness portion) 308b4 of the flow
rectifying plate.
In the condition that the housing 302a of the process cartridge 302 is
completely mounted within the printer 300 (FIGS. 20, 23A and 23B), the air
flows in the printer 300 as air flows W.sub.1 -W.sub.9. Particularly, as
shown by the air flow W.sub.4, the air flow passing between the housing
302a of the process cartridge 302 and a plate 312 of the printer impinges
against a wall 308a (attachment portion 308b2) of the position regulating
member 308 for the process cartridge 302. Then, this air flow passes
through between the housing 302a and the flow rectifying plate 308b and
between the housing 302a and the cover 309a of the protection member.
Thus, the housing 302a of the process cartridge 302 is hard to be receive
the heat from the fixing device 14, thus suppressing the increase in the
temperature in the cartridge 302. Incidentally, in the illustrated
embodiment, while the clearance between the housing 302a and the cover
309a of the protection member was selected to have a value of about 5
mm-10 mm, the clearance is not limited to this value.
A further embodiment of the present invention is shown in FIG. 24. In this
embodiment, a protection member 309 is divided into several segments
hinged together at points 309g, 309h and 309i. When the projection member
is opened, it is folded into two at the hinge 309h to face their inner
surface (facing the image bearing member) to each other. Now, when the fan
15 is rotated, the air flow W.sub.1 sucked from the air introduction
opening 300a flows around the process cartridge 302 (air flow W.sub.3) to
reach the protection member 309 and then flows toward the fan 15 (air flow
W.sub.4). In this case, air flows W.sub.6 flowing along the end surfaces
of the process cartridge are restricted by the protection member 309 to
lose their powers. These air flows become a part of the natural convection
as shown by the arrows W.sub.6 by the convection of heat from the fixing
device 14, and are ejected by the fan 15 out of the printer as shown by
the arrows W.sub.7, W.sub.8.
Therefore, according to the present invention, it is possible to prevent
the heat generated by the fixing device 14 from flowing toward the
cartridge mounting direction. Incidentally, also in this embodiment, the
air flow W.sub.2 taken from the sheet supply portion passes through the
proximity of the photosensitive member 5, and a part of this air flow
passes through between the housing 302a and the protection member 309 and
is sucked by the fan 15 (air flow W.sub.9).
The other embodiment of the present invention is shown in FIG. 25. In this
embodiment, ambient air taken through the air introduction opening 300a by
the rotation of the fan 15 passes around the process cartridge 302 and is
sucked into the fan 15 (air flows W.sub.1, W.sub.3, W.sub.4, W.sub.5,
W.sub.7 and W.sub.8). According to this embodiment, the air flowing along
the upper surface 302a of the process cartridge is directed to the
protection member 309 as shown by the arrow W.sub.4 and then is ejected
out of the printer. On the other hand, the air flows W.sub.6 passing along
the end surfaces of the process cartridge 302 are blocked by the
protection member 309 not to enter below the protection member 309.
Further, according to this embodiment, the ambient air (W.sub.2) taken
through the air introduction opening 300a passes through the proximity of
the photosensitive member 5 and then passes mainly between the housing
302a and the protection member 309 not to progress toward the fixing
device 14, because it is blocked by the protection member 309 so that it
is not influenced upon the fan 15. Thus, it is possible to prevent the
distortion of the image formed on the sheet P (before fixing) due to the
air flow.
Incidentally, in the above embodiments, while an example that a heat fixing
device is used as the fixing device was explained, the present invention
is not limited to this example. For example, a pressure fixing device may
be used. Further, other than the heat fixing device, although motors,
exposure lamp and the like also generate the heat in the image forming
system, the present invention is also effective to the generation of heat
from such elements.
Further, the clearance (distance) between the housing of the process
cartridge and the cover can be appropriately selected in accordance with
the designs of the process cartridge and the image forming system;
however, such clearance may be about 2 mm-50 mm, and preferably 3 mm-40
mm, and most preferably 5 mm-20 mm. If the clearance is smaller than about
2 mm, the sufficient cooling ability cannot sometimes be obtained
(However, even if the clearance is about 1 mm, some cooling ability can be
obtained in comparison with the case where there is no clearance);
whereas, if the clearance is greater than about 50 mm, the image forming
system will become large-sized.
Incidentally, the above-mentioned process cartridge incorporates therein an
image bearing member (for example, electrophotographic photo-sensitive
member and the like), and at least one of a charger means, developing
means and cleaning means (action means) as a unit which can removably
mounted within an image forming system. More specifically, the process
cartridge incorporates therein a charger means, developing means or
cleaning means, and an electrophotographic photosensitive member as a unit
which can be removably mounted within an image forming system (for
example, a copying machine, laser beam printer or the like); or
incorporates therein at least one of a charger means, developing means and
cleaning means, and an electrophotographic photosensitive member as a unit
which can be removably mounted within an image forming system (for
example, a copying machine, laser beam printer or the like); or
incorporates therein at least a developing means and an
electrophotographic photosensitive member as a unit which can be removably
mounted within an image forming system (for example, a copying machine,
laser beam printer or the like).
As mentioned above, according to the present invention, it is possible to
provide a process cartridge and an image forming system which can
remarkably enhance the cooling ability for the process cartridge by air
flows.
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